Patent GB-709158-A (GB)
Title: Methods of automatically positioning work prior to machining
IPC: B24B47/06
Filed: 1952-05-07
Abstract: 709,158. Machine tool details. JONES & SHIPMAN, Ltd., A. A., and HOULDSWORTH, J. May 5, 1953 [May 7, 1952], No. 11535/52. Class 83 (3). [Also in Group XXIII] Means for positioning the worktable 4 of a grinding or other cutting machine comprises a fluid control valve 15, Fig. 2, having a movable valve element 18 connected with a mechanical transmission including a part 10 settable to a selected position in the path of a reference face 8, Figs. 1 and 2, on the work and arranged, when contacted and moved by this face, to actuate the valve automatically whereby the table-operating fluid motor 25 stops the table at the required end position for grinding the work. The machine is described for grinding from a face 9 up to one end of the work 1 which face is a prescribed distance from the reference face 8. The work is rotatably mounted on the table 4 which is moved by the motor 25 to the extent necessary to bring that part of the work to be ground opposite a grinding wheel 6. The face 8 is arranged to coact with the nose 19 of the lever 10 which is adjustably mounted on a slide 12 on the machine bed and connected by an adjustable link 14 with a lever 13 engaging between a stop 16 and the end of the spring-urged plunger 18. The plunger 18 controls a fluid supply port 21, exhaust ports 22 and ports 23, 24 leading through a hand-controlled or automatic valve 26 to the opposite ends of the motor 25. With valve 26 in the position shown, the valve 15 is ineffective and the fluid connections are such that the motor 25 moves the table to its withdrawn position. In operation, the mounting of the lever 10 is first moved on its slide 12 to provide for the desired final positioning of the table relatively to the grinding wheel, the length of the link 14 being adjusted correspondingly. The valve 26 is then set to place the motor 25 under the control of the valve 15 through the ports 21, 22 to advance the table. When the reference face 8 actuates the lever 10, the plunger 18 is moved to close the ports 21, 22 whereby the table is brought to rest, and the grinding wheel 6 is then fed inwardly for the grinding operation. As the table reaches its final position, the valve 15 opens the supply of fluid through the valve 26 and line 36 to a split-block clamp 32 to grip the piston rod 31 of the motor 25 and so hold the table in position. At the same time, the lever 10 is withdrawn from contact with the face 8 by increasing the length of link 14 by admitting pressure fluid from the line 36 to a cylinder-andpiston 40 incorporated in the link ; the operative extension of this link is ensured by arranging an end stop 43 in the valve 15 and providing for fluid from the line 36 to pass to a chamber 44 in the valve 15 for the purpose of clamping the plunger 18. If desired, the means for withdrawing the lever 10 may be arranged instead between the lever 13 and plunger 18. An emergency stop 45, Fig. 1, is provided in case the table should over-travel. The outer face 46 of the head 7 of the work may alternatively be used as the reference face by arranging for it to be engaged by the nose of a spring-pressed lever 50, Fig. 3 (not shown), which is mounted on the table or workhead for contacting the lever 10 and actuating the stop mechanism as described above. A fluid pressure device is provided for withdrawing the lever from contact with the face 46 when the table is finally positioned, such device being connected with the line 36 through a flexible hose which, in this arrangement, would be detached from its normal connection with the device 40. The nose 19 on the lever 10 may be adjustable to co-operate with different kinds of reference faces. The control valve 15 may be constructed as described in Specification 666,996, [Group XXIX].